Seal arrangement with encoder and magnetization head for the encoder

ABSTRACT

The invention relates to a seal arrangement for sealing off at least one radial interspace between at least one bearing ring which can rotate and at least one rotationally fixed bearing ring. The seal arrangement is provided with at least a first carrier, the first carrier carrying at least one resilient seal and being fixed to a rotationally fixed bearing ring, and a second carrier, the second carrier being fixed to the bearing ring that can rotate and carrying at least one encoder. The encoder has an outwardly oriented circumferential surface in the shape of a truncated circular cone.

CROSS REFERENCE TO A RELATED APPLICATION

The present application is a Divisional Application of Ser. No.10/803,412 filed Mar. 18, 2004, which application claims the benefit andpriority of German Application Serial No 103 38 960.1, filed Aug. 25,2003, incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a seal arrangement for sealing off at least oneradial interspace between at least one inner bearing ring and at leastone outer bearing ring. It relates more particularly to a sealarrangement provided with at least one first carrier, the first carriercarrying at least one resilient seal, and a second carrier, the secondcarrier carrying at least one encoder, and the encoder having anoutwardly oriented circumferential surface shaped as a truncatedcircular cone.

An encoder on a seal of a known type is described in U.S. Pat. No.6,329,814 B1. U.S. Pat. No. 6,329,814 B1 discusses a problem of limitedavailable space for the installation of a seal arrangement with anencoder on the bearing. The problem is circumvented in that example byan enlarged magnetized active surface and, optionally, by arranging theencoder radially on the outside of the outer ring.

However, this solution is still only partly effective because of thelimited radial space between the inner bearing ring and the outerbearing ring. Further, an encoder cannot be arranged radially on theoutside of the outer bearing ring in every case, since, because of theconnecting structures, no space or too little space is frequentlyavailable for such an arrangement. In addition, an encoder arrangedradially on the outer bearing ring can be integrated only withdifficulty into a seal constructed as one structural unit. A seal ofthis type becomes very complicated, is difficult to install, and doesnot provide sufficient protection for the encoder against environmentalinfluences.

U.S. Pat. No. 6,329,814 B1 also describes some advantages provided bythe polarization of an encoder with a circumferential surface in theshape of a truncated circular cone, as compared with the polarization ofcircularly cylindrical and outwardly oriented active outer surfaces.

SUMMARY OF THE INVENTION

A first aspect of the invention provides a seal arrangement with anencoder whose encoder is provided with an outer circumferential surfaceshaped as a truncated circular cone, in which the advantages of thisencoder are utilized, which is of space-saving design and which can beproduced and installed simply and cost-effectively. Furthermore, amagnetization head for an encoder is provided, with which such anencoder can be polarized in an improved manner.

The invention is directed generally to a seal arrangement which sealsoff at least one radial interspace between at least one bearing ringwhich can rotate and at least one rotationally fixed bearing ring. Theseal arrangement is provided with a least one first carrier, the firstcarrier carrying at least one resilient seal and being fixed to arotationally fixed bearing ring; a second carrier, the second carrierbeing fixed to the bearing ring that can rotate and carrying at leastone encoder, and the encoder having an outwardly orientedcircumferential surface of a truncated circular cone; and a dirtdeflector, the dirt deflector and the first carrier being arranged suchthat they can rotate relative to each other, wherein the seal bears atleast on the dirt deflector; and the encoder being arranged outside theinterspace and engaging around the bearing ring that can rotate.

There may also be a covering element, the encoder being covered radiallyand axially by the covering element, the covering element being fixed toone of the bearing rings. The covering element at least partly coversthe seal. The covering element is preferably non-ferromagnetic materialand may be formed in one piece with the first carrier.

More specifically, the covering element may be fixed to a radially outersurface section of the rotationally fixed bearing ring.

The dirt deflector and the second carrier may be formed from sheet metalin one piece. The seal may bear on the dirt deflector in the radial oraxial direction with at least one sealing lip. The seal may beardirectly on the bearing ring that can rotate, or radially on the secondcarrier. The seal and the dirt deflector may enclose between them anannular hollow space filled with a lubricating grease.

The dirt deflector may be a sheet metal ring with an angled crosssection having two limbs aligned at right angles to each other, theencoder engaging radially around at least one of the limbs. The secondcarrier may be a sheet metal ring with two hollow cylindrical sectionsthat point away from each other, the sections being connected to eachother by a web which is disk-like and goes radially away from thebearing ring that can rotate and, in the process, one of the sectionsaccommodates the encoder radially and the other of the sections isseated on the bearing ring that can rotate.

The encoder is advantageously formed from a resilient material.

A magnetization head has on its inner circumference an innercircumferential surface defining an inner cone, the innercircumferential surface corresponding with the circumferential surfaceof the truncated cone of the encoder. The rectilinear innercircumferential lines of the inner circumferential surface describingthe inner cone and inclined with respect to the axis of rotation of themagnetization head are preferably longer than the circumferential linesoriented in the same direction as the inner circumferential lines anddescribing the circumferential surface of the encoder. Further, thesmallest inner cone diameter of the inner cone is preferably smallerthan the smallest external diameter of the truncated circular cone. Alsopreferably, the inner circumferential surface of the magnetization headthat is seated on the encoder during polarization, bearing on thecircumferential surface, projects axially beyond the circumferentialsurface of the encoder on both sides.

In this disclosure, the term encoder stands for one or more single-partor multi-part encoders which is/are arranged on the circumferential sideof the bearing axis. The encoder is made from magnetizable material andis alternately polarized. Examples of such materials are plastics suchas polyamides whose magnetizable material has bainitic ferrite orstrontium ferrite added to it, or plastics which have magnetizableinserts. Alternatively, the encoder may be made of magnetizable metal.

At least one sensor, arranged on the outside, around the sealarrangement and encoder, may pick up signals from the encoder,irrespective of possibly otherwise oriented scattering of these signals,taking account of the angle of inclination of the cone, or may transmitsignals in the direction of the encoder. The sensor or sensors may beseated on the fixed bearing ring, which cannot move in relation to therotating bearing ring, or may be fixed to the vehicle in another way.

The encoder is provided with a surface which faces in the direction ofthe sensor, and is alternatively signal-accepting, signal-reflecting orsignal-generating and thus active. The active surface points radiallyoutward and forms an (outer) circumferential surface which defines atruncated circular cone. The radially outwardly oriented active surfaceof the encoder is preferably formed on a one-part encoder in the form ofa rotationally symmetrical hollow truncated cone or assembled in anumber of parts from a plurality of segments defining such a truncatedcone. The encoder is arranged on the rotating bearing ring via a carrierpreferably shaped from sheet metal.

The substantial advantages of an encoder with the circumferentialsurface in the shape of a truncated circular cone are a uniform magneticfield strength on the entire periphery and high accuracy of the pitch ofthe polarization of the magnetized encoder, which are provided by thefollowing factors:

The magnetization head for magnetizing by use of one (mating) inner conematched to the truncated cone is centered on the truncated cone of theencoder. This avoids the inaccuracies which occur when magnetizingencoders with a cylindrically radially outwardly oriented or axiallyaligned annular active surface as a result of the axial offset of themid-axis of the magnetization head in relation to the mid-axis of theencoder.

The magnetization head is seated directly on the encoder to bemagnetized. Erroneous alignments, such as an axial offset betweenmagnetization head and encoder, are avoided. The axial offset duringmagnetization occurs when a gap exists between a magnetization head andan encoder with a cylindrically radially outwardly oriented or axiallyaligned annular active surface.

When resilient materials are used as a material for the encoder, theencoder nestles with a resiliently compliant surface on the insideagainst the magnetization head when the magnetization head bears underpressure on the encoder during magnetization. Compliant materials ofthis type are, for example, NBR (acrylonitrile butadiene rubber).

A second aspect of the invention provides a magnetization head formagnetizing an encoder of a seal arrangement according to the firstaspect of the invention which, on its inner circumference, has apolarizing inner circumferential surface defining an inner cone, whichcorresponds to the active circumferential surface of the truncated coneof the encoder. The rectilinear inner circumferential lines of the innercircumferential surface, describing the inner cone and inclined withrespect to the axis of rotation of the magnetization head, are in thiscase at least as long as and preferably longer than the rectilinearcircumferential lines of the active circumferential surface of theencoder, oriented in the same direction as the inner circumferentiallines. The amount by which the inner circumferential lines are longer inthis case takes account of the production tolerances, occurring in themass production of encoders, of the axial width of the encoder (i.e.,the maximum height of the truncated cone oriented in the same directionas the axis of rotation). Furthermore, the smallest inner cone diameterof the inner cone is smaller than the smallest outer diameter of thetruncated circular cone. The inner circumferential surface of themagnetization head seated on the encoder bears on the circumferentialsurface of the encoder during polarization. The inner circumferentialsurface projects beyond the circumferential surface of the encoderaxially on both sides. The inner cone of the magnetization head in anycase engages over and accordingly magnetizes the entire activecircumferential surface of each encoder, irrespective of widthfluctuations among a series of encoders of identical type/identicaldesign or in the case of encoders of the same nominal dimensions.

The cone angle of the magnetization head or encoder is preferably5°<=α<=15°.

The interspace of the bearing is predefined by the geometry of the outerbearing ring and the shape of the inner bearing ring. Radially, theinterspace is bounded by the inner circumferential surface of thenarrower, normally outer, bearing ring and also by the outercircumferential surface of the broader, normally inner, bearing ring.The antifriction elements and the cages of the bearing are arranged inthe interspace. The interspace ends axially at imaginary planes whichare aligned perpendicular to the bearing axis and which originate fromthe end faces of the bearing ring (optionally the inner or outer ring)which is narrowest in terms of its axial width. The inner ring is as arule broader than the outer ring and thus pierces at least one of theseplanes at the side of the bearing on which the encoder adjoins theinterspace. The encoder optionally adjoins the outer ring or interspaceaxially and engages around the inner ring circumferentially.

The arrangement of the encoder outside the interspace offers theadvantage that the encoder can be provided with a substantially largeractive surface. The sensor unit with a radially outwardly orientedencoder takes up less radial height, as compared with axially alignedencoders. The gain in overall space can additionally be utilized for anoptimum shape of the seal, since only a little radial space is availablefor the installation of a seal.

In wheel bearing units, the outer bearing rings frequently migrateaxially outward as compared with their ideal position in relation to theinner bearing ring, by the order of magnitude of normal operationalplay. In seal arrangements in which the encoder is sensed in the axialdirection by the sensor, the outward migration influences the gap spacein between encoder and sensor, which is axial in this case. As the gapwidth increases, the transmission becomes more inaccurate. By contrast,the gap dimension, oriented in the same direction as the inclination ofthe truncated cone, between the encoder and the sensor of a sealarrangement according to the invention is not influenced by outwardmigration of the bearing ring. The possible axial offset between sensorand encoder produced by the outward migration of the outer bearing ringis merely taken into account from the start in the design of the overallwidth of the encoder. The sensor arrangement is thus less susceptible tofaults.

The seal arrangement protected by a covering element is optimallyprotected with all constituent parts protected against externalenvironmental influences. The covering element is designed in the formof a covering cap and, depending on further functions additional to thecovering function, is preferably formed from non-ferromagnetic plasticsor metals. The covering element and the sheet metal carrier arepreferably shaped cold by cold forming, such as by bending, rolling,drawing, embossing or punching. The covering element assists the sealingfunction of the seal arrangement of the bearing.

The seal arrangement is adapted for installation in the wheel bearingsets of all conceivable motor vehicles. This relates in particular totwo-row and four-row bearing sets but also all other conceivable wheelbearing sets with rollers or balls as antifriction elements, inparticular in inclined roller or inclined ball bearing design. The wheelbearing sets optionally have single-piece bearing rings with runningtracks for all of the rows, divided bearing rings or a bearing ring foreach row and combinations of these aforementioned configurations. Theinner bearing rings can rotate either in relation to the outer bearingring(s) or the outer can rotate in relation to the inner. One of thebearing rings is preferably fixed to the vehicle in relation to therotatable bearing rings. Inner bearing rings are preferably seated on ahub, the mounting being set against the hub without play by a flangededge. The outer bearing ring is optionally formed in one piece with oneor more flanges for fixing the wheel bearing unit on the vehicle side orwheel side, or these bearing rings may be introduced into acorresponding flanged housing.

The seal is formed of the materials normally used, such as elastomers,and alternatively also may have radially prestressing endless spiralsprings.

The seal arrangement is preferably formed as a cartridge seal. Theimportant elements of the seal arrangement are assembled to form anintrinsically self-contained structural unit comprising carriers,covering cap, seal and encoder (cartridge seal). Stock keeping,transport and installation in the bearing unit are therefore simplified.The seal arrangement can be interchanged with seal arrangementsaccording to the prior art without changes necessitated by overall spacehaving to be made in the design of the bearing unit.

Other features and advantages of the present invention will becomeapparent from the following description of embodiments of the inventionwhich refers to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 4 respectively show partial cross-sectional views ofexemplary seal arrangements according to embodiments of the invention.

FIGS. 5 and 6 respectively show radially and axially orientedmagnetization heads according to the prior art and their alignment inrelation to corresponding encoders during polarization.

FIG. 7 shows, in schematic form, a magnetization head for an encoder ina seal arrangement according to an embodiment of the invention and itsalignment in relation to the encoder.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

A seal arrangement 1 with an encoder 2 is illustrated in sectionalrepresentation in FIG. 1. The encoder 2 is integrated into the sealarrangement 1. The seal arrangement 1 has a first carrier 3, to which aseal 4 is fixed. Furthermore, the seal arrangement 1 has a secondcarrier 5 with the encoder 2. The encoder 2 is a hollow ring of plasticshaped like a hollow truncated cone with optionally magneticallypolarized additions or inserts. On the circumferential side, the encoder2 has an outwardly oriented circumferential surface 2 a shaped as atruncated circular cone.

An outer bearing ring 7,which in this case is a rotationally fixedbearing ring, is assigned to a vehicle, not illustrated, such that it isfixed against rotation, and an inner bearing ring 8 can rotate relativeto the outer bearing ring 7.

The seal arrangement 1 is assigned a sensor 9. The sensor 9 is seatedradially outside the seal arrangement 2 and radially over the sealarrangement 2, either bearing on the seal arrangement (not shown) orseparated from the latter by a gap 13.

The seal arrangement 1 is mostly covered by a covering element 6. Thecovering element 6 is formed from sheet metal in the manner of a cap inone piece with the first carrier 3 and on the outside is fixed to asurface section 7 a of the outer bearing ring 7. For this purpose, thecovering element 6 is seated with a hollow cylindrical section 6 apressed on the surface section 7 a and from there extends axially awayfrom the outer bearing ring 7, between the sensor 9 and the encoder 2.Then the covering element 6 extends radially inward in a disk-likesection 6 b. An interspace 10 is bounded on the side of the encoder 2 bythe radial plane E, which runs through the front surface 7 b of theouter bearing ring 7. The encoder 2 is covered radially and axially andthe interspace 10 is covered axially with respect to the outside by thesection 6 b and thereby protected against contamination.

The covering element 6 finally extends into a hollow cylindrical section6 c which is angled away from the section 6 b and runs axially in thedirection of the antifriction elements 18. The seal 4 is fixed to thesection 6 c. The seal 4 has a sealing lip 11 with two sealing edges 11 aand 11 b. The sealing edge 11 a bears in the axial direction on a dirtdeflector 12.

The dirt deflector 12 is an angled ring whose one limb 12 a is orientedradially outward away from the inner bearing ring 8. In addition, thedirt deflector 12 is formed from sheet metal in one piece with thesecond carrier 5 and, for this purpose, is connected to the carrier 5via the other limb 12 b. The second sealing edge 11 b bears radially onthe limb 12 b, prestressed in an intensified manner by the action of anendless spiral spring 14. The section of the sealing lip 11 bounded bythe sealing edges 11 a and 11 b, and portions of the limbs 12 a and 12 bbound an annular hollow space 15, which is optionally filled withgrease. The limb 12 a forms a gap seal, defined by the gap 16, betweenthe dirt deflector 12 and the covering element 6 and between the dirtdeflector 12 and the seal 4. Liquid that has even penetrated into theantechamber 17 gets out away from the seal 4 again through the gap 16 asa result of gravitational or centrifugal forces.

The second carrier 5 merges at the limb 12 b into the dirt deflector 12and thus initially extends, at least partly radially between the seal 4and the inner bearing ring 8, axially in the direction of theantifriction elements 18 and is then angled over radially outward. Here,the carrier 5 runs in the form of a disk-like section 5 a axiallybetween the antifriction elements 18 and the cage 19 on one side, andradially outward between the seal 4, the dirt deflector 12 and thecovering element 6. From the section 5 a, a hollow cylindrical carryingsection 5 b is angled over, which points axially in the direction of thecovering element 6 and on which the encoder 2 is seated radially betweenthe carrying section 5 b and the section 6 a. The encoder 2 engagesaround the radially hollow cylindrical carrying section 5 b and thehollow cylindrical limb 12 b.

FIG. 2 shows a seal arrangement 20 comprising the encoder 2, a coveringelement 21 in the form of a sheet metal cover with a seal 22, andcomprising a dirt deflector 23. The covering element 21 is at the sametime the first carrier 24 and is seated on the rotationally fixed outerbearing ring 25. The covering element 21 covers the encoder 2 radiallywith respect to the outside, radially with respect to the inside and tothe antechamber 26, and the encoder 2 axially. The interspace 10 boundedby the radial plane E is protected axially by the dirt deflector 23 andthe seal 22 arranged after it.

The dirt deflector 23 is a separate angled sheet metal ring which isseated with one limb 23 a on the inner bearing ring 27. The seal 22bears radially with a sealing lip 22 a on the limb 23 a. A secondsealing lip 22 b is prestressed axially against a limb 23 b angled awayfrom the limb 23 a at right angles.

A second carrier 28 is a Z-shaped angled ring which is seated with ahollow cylindrical section 28 a on the inner bearing ring 27. A furtherhollow cylindrical section 28 b is formed, oriented in the directionopposite to the section 28 a, on a disk-like section 28 c connecting thesections 28 a and 28 b, and carries the encoder 2 radially on theoutside. The encoder 2 is formed from a resilient material withmagnetizable additives and engages radially around the outside of thelimb 23 a.

The seal arrangement 29 according to FIG. 3 has substantially the sameconstruction as the seal arrangement according to FIG. 2 but is providedwith a dirt deflector 30 whose limb 30 a, which is seated on the innerbearing ring 27, is shortened as compared with the limb 23 a. Axiallybetween the limb 30 a and the second carrier 28 there is a free spacewherein a sealing lip 31 a of a seal 31 fixed to the covering element 21between the second carrier 28 and the limb 30 a bears radially on theinner bearing ring 27. A further sealing lip 31 b bears radially on thelimb 30 a. Finally, a third sealing lip 31 c is prestressed axiallyagainst a limb 30 b of the dirt deflector 30.

The seal arrangement 32 according to FIG. 4 shows a further alternativeconfiguration having some features of the seal arrangements 20, 29described previously in FIGS. 2 and 3. However, in the seal arrangement32, a second carrier 33 has hollow cylindrical sections 33 a and 33 boriented in the same direction. The section 33 a in this case pointsaxially in the direction of the dirt deflector 30. The sealing lip 22 aof the seal 22 fixed to the covering element 21 bears radially on thesection 33 a. The sealing lip 22 b is prestressed axially against thelimb 30 b. The section 33 b of the second carrier 33 carries the encoder2 on its outer side and reaches radially around the section 33 a and thelimb 30 a.

FIG. 5 shows, in schematic form, a radial magnetization head 34 which,with a circularly cylindrical and radially inwardly facing polarizationsurface 34 a, engages around an encoder 35. On the outside, the encoder35 has a circularly cylindrical circumferential surface 35 a, which islocated radially opposite the polarization surface 34 a. The internaldiameter D is designed to be sufficiently large that, in any case, themagnetization head can still reach around even an encoder with thegreatest deviation T₁+T₂ from a nominal diameter d. Between an encoder35 whose diameter corresponds to the nominal diameter d and themagnetizable head 34, in the event of an unfavorable offset R, a maximumradial spacing of T₁+T₂ and, radially opposite, a radial spacing of 0may be formed. For encoders which, within this tolerance range, havesmaller diameters than the nominal diameter, the maximum radial spacing>T₁+T₂. The axis of rotation 34 b of the magnetization head 34 and theaxis of rotation 35 b of the encoder 35 are erroneously offset by theradial offset R in relation to each other, which, in the least favorablecase, corresponds to the value T₁+T₂.

FIG. 6 shows, in schematic form, an axial magnetization head 36 whichbears axially with an annular polarization surface 36 a on an annularactive surface 37 a of an encoder 37. The axis of rotation 36 b of themagnetization head 36 and the axis of rotation 37 b of the encoder 37may be erroneously offset by the radial offset R in relation to eachother.

As a consequence of the radial offset R, the finally magnetized encoder35 or 37 may be provided with fields which are adjacent to one anotherin the circumferential direction and alternately polarized from north tosouth, but which have widths distributed over the periphery whichdeviate from the intended (i.e., uniform) width and pitch of the fieldsin relation to one another, and thus are arranged with different pitches(i.e., pitch errors) in relation to one another.

FIG. 7 shows, in schematic form, a magnetization head 38 according to anembodiment of the invention having an inner circumferential surface 38 ashaped as an inner cone, which engages around a circumferential surface39 a of an encoder 39 shaped like a truncated cone and bears on thelatter. The cone of the magnetization head 38 and the truncated cone ofthe encoder 39 have at least approximately the same cone angle α, andthe height H₁ of the inner cone on the magnetization head 38 is greaterthan the height H₂ of the truncated cone of the encoder 39. The coneangle of the magnetization head or encoder is preferably 5°<=α<=15°. Thesmallest internal diameter D₁ of the cone of the magnetization head 38is smaller than the smallest external diameter d₁ of the truncated coneof the encoder 39, so that a space T remains axially between the frontfaces 38 c and 39 c. The rectilinear inner circumferential lines 40 ofthe inner circumferential surface 38 a are longer than the outercircumferential lines 41 of the circumferential surface 39 a of theencoder 39, so that the inner cone projects beyond the truncated cone onboth sides. The axes of rotation 38 b and 39 b of the magnetization head38 and of the encoder 39 are located coinciding with each other with nooffset. After the magnetization has been completed, the encoder 39therefore has polarized fields which are identical to one another andare arranged with no pitch error in relation to one another.

Although the present invention has been described in relation toparticular embodiments thereof, many other variations and modificationsand other uses will become apparent to those skilled in the art.Therefore, the present invention is not limited by the specificdisclosure herein.

1. A seal arrangement which seals off at least one radial interspacebetween a rotatable bearing ring and a rotationally fixed bearing ring,the seal arrangement comprising: a first carrier, the first carriercarrying a resilient seal and being fixed to said rotationally fixedbearing ring; a second carrier, the second carrier being fixed to therotatable bearing ring and carrying an encoder, the encoder having anoutwardly oriented circumferential surface which defines a truncatedcircular cone; and a dirt deflector, the dirt deflector and the firstcarrier being arranged such that they can rotate relative to each othersuch that the seal bears at least on the dirt deflector, the encoderbeing arranged outside the interspace and around the rotatable bearingring.
 2. The seal arrangement as claimed in claim 1, further comprisinga covering element, the encoder being covered radially and axially bythe covering element, the covering element being fixed to one of thebearing rings.
 3. The seal arrangement as claimed in claim 2, in whichthe covering element at least partly covers the seal.
 4. The sealarrangement as claimed in claim 2, in which the covering element isformed in one piece with the first carrier.
 5. The seal arrangement asclaimed in claim 2, in which the covering element is fixed to a radiallyouter surface section of the rotationally fixed bearing ring.
 6. Theseal arrangement as claimed in either one of claims 4 and 5, in whichthe covering element, starting from the rotationally fixed bearing ring,initially extends axially away from the rotationally fixed bearing ring,for being radially disposed between a sensor and the encoder, and coversthe encoder in the radial direction; the covering element then extendsradially and at least partly covers the encoder and the interspace inthe axial direction; and the covering element finally extends axially inthe direction toward the interspace while carrying the seal.
 7. The sealarrangement as claimed in either one of claims 4 and 5, in which thecovering element, starting from the rotationally fixed bearing ring,initially extends axially away from the rotationally fixed bearing ring,for being radially disposed between a sensor and the encoder, and coversthe encoder in the radial direction; the covering element then extendsradially and at least partly covers the encoder and the interspace inthe axial direction; the covering element then runs in the directiontoward the interspace radially between the encoder and the rotatablebearing ring; and the covering element finally extends radially in thedirection toward the rotatable the bearing ring while carrying the seal.8. The seal arrangement as claimed in claim 2, wherein said first andsecond carriers, said dirt deflector and said covering element areinterconnected to form a cartridge.
 9. The seal arrangement as claimedin claim 1, in which the seal bears on the dirt deflector in the axialdirection with at least one sealing lip.
 10. The seal arrangement asclaimed in claim 1, in which the seal bears radially on the dirtdeflector with at least one sealing lip.
 11. The seal arrangement asclaimed in claim 1, in which the seal bears directly on the rotatablebearing ring with at least one sealing lip.
 12. The seal arrangement asclaimed in claim 1, in which the seal bears radially on the secondcarrier with at least one sealing lip.
 13. The seal arrangement asclaimed in claim 1, in which the seal and the dirt deflector enclosebetween them an annular hollow space filled with a lubricating grease.14. The seal arrangement as claimed in claim 1, in which the dirtdeflector is a ring with an angled cross section having two limbsdisposed at right angles to each other, the encoder engaging radiallyaround at least one of the limbs.
 15. The seal arrangement as claimed inclaim 1, in which the second carrier is a ring with two hollowcylindrical sections that face away from each other, the sections beingconnected to each other by a web which is disk-like and extends radiallyaway from the rotatable bearing ring; wherein one of the sectionsaccommodates the encoder radially and the other of the sections isseated on the rotatable bearing ring.
 16. The seal arrangement asclaimed in claim 1, in which the encoder is formed from a resilientmaterial.
 17. In combination, a seal arrangement which seals off atleast one radial interspace between a rotatable bearing ring and arotationally fixed bearing ring, the seal arrangement comprising: afirst carrier, the first carrier carrying a resilient seal and beingfixed to said rotationally fixed bearing ring; a second carrier, thesecond carrier being fixed to the rotatable bearing ring and carrying anencoder, the encoder having an outwardly oriented circumferentialsurface which defines a truncated circular cone; and a dirt deflector,the dirt deflector and the first carrier being arranged such that theycan rotate relative to each other such that the seal bears at least onthe dirt deflector, the encoder being arranged outside the interspaceand around the rotatable bearing ring; and a magnetization head forpolarizing said encoder, in which the magnetization head has on itsinner circumference an inner circumferential surface defining an innercone, the inner circumferential surface corresponding with thecircumferential surface of the truncated cone of the encoder; therectilinear inner circumferential lines of the inner circumferentialsurface describing the inner cone being inclined with respect to theaxis of rotation of the magnetization head, and being longer than thecircumferential lines oriented in the same direction as the innercircumferential lines and describing the circumferential surface of theencoder.
 18. The combination as claimed in claim 17, in which thesmallest inner cone diameter of the inner cone is smaller than thesmallest external diameter of the truncated circular cone, and in whichthe inner circumferential surface of the magnetization head, which isseated on the encoder during polarization and bears on thecircumferential surface, projects axially beyond the circumferentialsurface of the encoder on both sides.